Transmission issues revisited...

9534 Views 67 Replies 6 Participants Last post by Novafrk, Mar 9, 2009

Novafrk

Discussion Starter · Oct 31, 2008

Hello all,

This morning I fired up the Honda to ride into work and take advantage of the warm snap. As I puttered through the neighborhood, I tried to shift into fourth gear... it wouldn't go... then it popped out of third... then it wouldn't stay in second... or first. It constantly wants to come out of gear. It's also making some rather "I'm not happy" noises, read crunching and grinding. I rode the bike last Sunday with out a single problem, no one has touched it... now this. I'll be pulling the engine out here pretty soon. No rush though I guess, with winter coming on. Sigh...

Novafrk / Eric

1 - 20 of 68 Posts

kirkn

· #2 · Oct 31, 2008

One of my Honda CM185 Twinstars did that when I bought it.

On that bike, as on most Honda twins & singles of that era, when you move the shift lever, the internal linkage rotates the shift drum, which slides the various gears back and forth. On the outboard end of the drum (opposite the shift lever) is a star wheel and a smaller, spring-loaded wheel rides on the star wheel. The little wheel rides in the notches of the star - one notch per gear. On my Twinstar, the bolt that holds the little wheel's arm came loose and let the little wheel slip off the star. There was no positive 'detent' when you shifted from gear to gear. Kept slipping out of gear.

I removed the clutch cover to discover all this. I simply put it back together and snugged up the loose bolt. Never had any more troubles.

Try that inspection,first, as you don't have to pull the motor - just the clutch cover.

Good luck with it,

Kirk

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tbpmusic

· #3 · Oct 31, 2008

Hmmm....

I think you're just fishing for another Homer Award :roll: :roll:

Seriously, check the shift shaft and the shift drum stuff under the clutch.
Sounds like it may not be working right under there.
We very seldom hear of problems with the 350 tranny itself.
Much more common to have real tranny problems on the 450's.

donny662

· #4 · Nov 1, 2008

Great picture, thanks!!! For you "old guys" this may have sounded like a Homer Award candidate

, but to me, this is completely new stuff.

66Sprint

· #5 · Nov 1, 2008

Donny, Some Hondas have more than one detent wheel (the 450 for instance).... These wheels rotate on an undersized "axle" so they may feel loose or "floppy".... As long as the hole in the wheel is round (not ovaled), smooth (not ragged inside), and it's not falling off, it should work correctly..... The "pins" in the "star" the "fingers" of the shifter pawl "grab" onto may be grooved or worn into a "notch"....If so, replace them ... The "fingers" themselves can be worn out, but this is very unusual to find in the Hondas......BUT, ANY obvious wear on any of these parts can be the culprit.....
The trans shifts while the shafts are rotating, so if it shifts smoothly and the detent drops all the way into the notches while the rear wheel is being spun, you should be good.......If in doubt, post pics and ask more questions..... Steve

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66Sprint

· #6 · Nov 1, 2008

Eric, the 350 uses a spring-loaded loose ball bearing as the detent...... There is a snap-ring on the shift shaft that often "pops-loose" (on the left side of the main cases) that could be causing your problems.... Without it in place, the shaft can move inwards which causes grinding noises and "hard" and incomplete shifts...... Dohh! to both of us for not checking this sooner!........Steve

tbpmusic

· #7 · Nov 1, 2008

Eric -

Unlike the 360 photo above, you'll find the 350 shifter stuff towards the top of the crankcase on that side, behind the clutch basket.

Again, it's pretty unusual for a 350 to have real tranny problems (though not unheard of).

Much more common in 450's, they had a "jump out of gear" problem in the earlier 5-speeds, related to defective engagement dogs in the gears themselves. It was so common that there was a "recall" (though they didn't call it that back in The Day) involving 2 countershaft gears and a shift fork. One of my K2's suffered from it, but was corrected with the warranty "kit" issued by Honda.

Novafrk

Discussion Starter · #8 · Nov 1, 2008

Thanks for all the advice guys... I'm on the "honey do" list today maybe I can sneek it in tonight, tomorrow for sure though. Mmmm that doughnut sure looks tasty...

crazypj

· #9 · Nov 4, 2008

I've seen more than one where the center bolt holding detente 'cam' in place has been loose (on various Honda's from mid 60's up)
Got my first S65 for £5.00 because if that exact reason
PJ

Novafrk

Discussion Starter · #10 · Nov 14, 2008

Well, I did manage to get out into the garage last Sunday or was it two ago... at any rate I discovered I needed the special tool to remove the oil filter housing. I received the tool today so by Monday I hope to have the old girl at least diagnosed. Saturday is partially booked I'm driving out to pick up a frame for my Triumph project. Check out that thread for an update if you like.

Eric/Novafrk

Novafrk

Discussion Starter · #11 · Nov 14, 2008

Hello all,

Boy that tool works great. The big round bolt/screw is loose. Do you think this is what was causing my shifting woes? Is this linkage supposed to be adjusted a certain way or do I just tighten this up where the wear/sludge marks are and give it a shot? The book is a little vague about adjustments unless I'm in the wrong part of the manual.

Thanks in advance,

Eric

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66Sprint

· #12 · Nov 15, 2008

Eric, I'm fairly certain that the "points" of the star shaped cam are supposed to cover and retain the "pins" that the shift pawl uses to rotate the drum.(It appears to me that the point of the star that is almost at 12 O'clock should be covering the pin at the 10:30 position.... At least they do on the last transmission I was into (the 90cc).... That phillips head "bolt" should have a shoulder so the area that guides the roller detent bar stays consistant, and it should be tight.....Otherwise, the "star" can rotate (or NOT rotate when the drum does,) and it detents the drum elsewhere but "in" the gears..... Bill will/can verify or explain better..... BUT YEP, thats the problem!....Steve

tbpmusic

· #13 · Nov 15, 2008

I think Steve is right, but I can't really tell anything from the photo.
The star-shaped plate should be indexed to the drum with a pin - it should only be able to go on there one way.
You'll need to pull out the shift shaft and disassemble the detent levers and springs - that's a real pain in the butt (not to take apart, but to get back together), but the only way to get it all lined up right.

Novafrk

Discussion Starter · #14 · Nov 15, 2008

Bill,

How are you? Can that be done with the engine in the bike or does this mean its comming back out of the bike?

Eric

66Sprint

· #15 · Nov 15, 2008

Eric.... It can be done "in" the frame/on the bike..... I believe you will find that the index pin is missing or broken (some models/years didn't have them) ....after everything is back on the drum, detents, and shift pawl, try going through the gears while spinning the rear wheel..... That detent wheel SHOULD roll over each "point" into each star "pocket" and lock the trans in the gears.....If so, THEN put the clutch back on/ rebuild/button her up...... Steve

tbpmusic

· #16 · Nov 15, 2008

Novafrk said:
Bill,

How are you? Can that be done with the engine in the bike or does this mean its comming back out of the bike?

Eric

Yeah, you can do that without pulling the engine.

But if the shift drum itself is buggered, you have to pull the engine and split the cases to do that.

The fun just never ends, does it??

Novafrk

Discussion Starter · #17 · Nov 15, 2008

Ok, so if I'm understanding everyone correctly. The detent wheel (star shaped plate) is loose with the only thing holding it in place is the large headed phillips bolt. And If I realign it and lock it down I'll be back in business? Did I get that right?

Eric

tbpmusic

· #18 · Nov 15, 2008

Novafrk said:
Ok, so if I'm understanding everyone correctly. The detent wheel (star shaped plate) is loose with the only thing holding it in place is the large headed phillips bolt. And If I realign it and lock it down I'll be back in business? Did I get that right?

Eric

Eric -

Like I said, I'm pretty sure there's a "locating" pin thing that the star-shaped wheel locks into, to secure it to the end of the shift drum - as well as the screw that holds it in place.
So it will only go back in one way.
If you look at the end of the shift drum, you should see a little hole near the circumference that a little pin goes into, which fits into a corresponding hole in the star wheel.

Does that make sense??

66Sprint

· #19 · Nov 15, 2008

Eric, To clarify Bill's statement..... There is either a separate locating pin, OR one of the larger pins on the drum (that the star covers) will be a tad longer than the others...It will seat in a depression on the underside of the star, and locking the large Phillips bolt down retains everything in alignment....... What happened, is the phillips came loose allowing the star to flop enough to come off that pin, then it spun separately from the drum and the roller wheel engaging the "pocket" no longer stopped the drum in exactly the correct place.... hence overshifts or undershifts resulting in "missed" gears or "jumping out" of gear........ Steve

Novafrk

Discussion Starter · #20 · Nov 16, 2008

So if I line up the star with the wear marks(as seen in the picture), then rotated the drum to line up with said pin I should be good to go?

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